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Function For applying on luminous objects, as gas or electric lamps. |
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Description The cylindrical diaphragm lets a set of light rays pass across an asymmetric arrow formed by holes pierced along the lateral surface. | |||
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Function Point source for optical experiments. |
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Description A concave mirror directs the light produced by a lamp into a funnel that ends with a little hole. The ensemble is in varnished metal. | |||
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Function Source for optical experiments. |
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Description Some bits of coals are placed at right angle and are adjustable separately or simultaneously thanks to two coaxial buttons, placed at the end of the screw that controls the above coil. The coals can have a diameter from 5 to 18 mm; the lamp can work with a current from 3 to 20 amperes, in alternate or direct current. The isolation of the binding posts for the bits of coals is made with a mica strip. The removable sheet iron cover has a lateral window closed by a mica sheet, that can easily be blackened with smoke to observe the size of the arc. The body of the arc is hinged on a 14-millimetre tube, sliding in the support column. The lamp can be oriented in all directions. | |||
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Function Apparatus used to follow the apparent path of the Sun. |
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Description The apparatus is used to deflect the rays of the Sun towards the inside of a laboratory of physics to have a source of light. The model is completely in brass, with a silver plate mirror and a black mirror. The control is made from the inside with a tangent screw for the rotation on the horizontal axis of all the apparatus and with a rack for the mirror. A diaphragm is enclosed with a rectangular variable slit. | |||
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Function To measure the luminous intensity of a source. |
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Description After the decision of the Congress of Geneva, the most commonly used standard source is that proposed by Siemens and studied by Hefner. In this we can burn the amyl acetate with a solid wick, that fills completely the tube of nickel silver which has an 8-millimetre internal diameter and is 3-mm thick. The height of the flame, measured 10 minutes after the lighting, must be 40 mm and it is controlled thanks to a finishing line formed by an obscura camera supplied with the lamp. In this case and when the flame burns in calm and pure air, the value of the source is 0.053 Violle unities. | |||
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Function Apparatus for illustrating the rectilinear propagation of the light, for the shadows and for Rumford’s photometer. |
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Description The apparatus includes: a paper screen on a wooden frame with a foot that holds it vertically according to its height and length, a brass foot with a column with a set screw on which we can fix a darken metallic disk for shadows and half-lights; a cardboard disk with a central hole for the rectilinear propagation of the light and for the obscura camera, a darken metallic pole for Rumford’s photometer; a support for three candles placed at the vertexes of an equilateral triangle. For the rectilinear propagation and the obscura camera we use the candlestick, the cardboard disk and the screen. For the shadows and the half-lights we use the candlestick, the metallic disk and the screen. For Rumford’s photometer we use the metallic pole, the screen, a candle and a group of four candles. | |||
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Function To measure the luminous intensity. |
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Description The Bunsen photometer is of a grease spot type, with a screen made of interchangeable paper that can be put upside down for two readings. There is also a mirror on both sides of the screen. One of the board guides is divided in cm with the zero in the centre. | |||
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School Function To deduce the number of the images of the same subject formed by two angular mirrors. |
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Description If n is the number of the virtual images and a the angle between the two mirrors, we have n = 360/a - 1. The two plane mirrors, assembled on a brass frame can turn because they are hinged on a steel axis, supported by a vertical column. By unthreading the axis of the hinge, the two mirrors can be fixed vertically on the basis by four brass buttons, and so we have an apparatus with parallel mirrors with an infinite succession of images. A disk with one side red and the other green is supported by a metallic foot and is used as the object. | |||
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Function To study the characteristics of convex mirrors. |
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Description The mirror has a 20 cm diameter. The 50 cm focal distance is the best for normal optics experiments. The frame is made of a brass ring turning around a horizontal diameter, supported by a fork with changeable height, placed on a cast iron tripod, with a brass column raising and turning on the vertical axis. | |||
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Function To study the characteristics of parabolic mirrors. |
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Description Mirror with a metallic frame turning around a horizontal diameter. The ensemble is sustained by a solid iron prismatic frame. | |||
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Function |
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Description The cylindrical reflecting glass surface is placed on a metallic frame; size 130 x 190 mm. | |||
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Function For studies on geometrical optics. |
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Description The above bar slides at friction; both can be fixed on the chosen position with set screws. In this way the lens centring is made quickly, as it regards only the height. The apparatus is used for lenses from 15 mm. to 100 mm. | |||
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Function For studies on geometrical optics. |
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Description A set of lenses, diameter 70 mm, are mounted on rings rotating on a horizontal diameter. The rings are sustained by forks with variable height placed on a circular basis. The ensemble in made of brass. All the types of spherical lenses are present.
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Function To study the reflection, refraction and the total internal reflection. |
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Description A vertical circle of 20 cm diameter is divided, on the four quadrants, from 0 to 90 degrees, and it is supported by a tripod. Two independent alidades with an index turn on the axe of the circle. In the circle an index on the alidades gives the angle that they form with the vertical diameter. This is represented by a ruler that individualizes the perpendicular to the reflecting or refracting surface in the incidence point. Two rules, sliding perpendicularly to the vertical diameter, allow the reading of the sine of the angles. The first alidade, that is longer, sustains a rotating flat mirror, that is used to direct a light beam across the rectangular slit of a diaphragm fixed under the mirror. The second alidade sustains a circular frame with a glass polished with emery and a black track to collect the reflected or refracted beam. On the horizontal diameter of the circle we can fix a flat mirror or a very thick half-cylindrical glass block, with the flat side up. With the mirror we can verify the reflection law; with the half-cylindrical glass we can verify the laws of refraction, and the total internal reflection and we can determinate with good approximation the critical angle of this glass, and the refraction index. | |||
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Function Toy that can supply new ideas for geometrical designs. |
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Description It is made with a cardboard tube covered with imitation leather and brass trimmings at the ends. The case that holds the coloured objects is turning on its axis and the objects stand between two glasses, one of them polished with emery. The reflecting strips are black glasses 30 degree inclined. All the parts are fixed with screws and can be dismounted. | |||
